This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The purpose of this protocol is to establish a model system to study the genetic basis of reproductive aging. The project will study a pedigreed colony of 500 naturally aging adult baboons. The reproductive cycle will be monitored by observation and the animal bled on day 5 and 25 of the menstrual cycle. The data and analysis will identify human genetic regions responsible for variation in reproductive indices of senescence. The colony will provide extensive resources on senescence pathology and gene expression profiles of aging. The combined scale, economy, experimental environment, pedigree and marker set of the aging baboon offers an unprecedented resource to advance our understanding of aging and health in humans.